<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .basic{
            width: 150px;
            height: 150px;
            border: 10px solid green;
            padding: 10px;
            background-color: red;
        }
        .content{
            width: 150px;
            height: 150px;
            border: 10px solid green;
            padding: 10px;
            
            /* 计算方式不包括：padding\border */
            /* box-sizing: border-box; */

            /* 计算方式包括: padding\border */
            box-sizing: content-box;
            background-color: red;
        }
    </style>
</head>
<body>
    <div class="basic">这是一个盒子模型</div>
    <div class="content">盒子模型：：content-box</div>
</body>
</html>